Corneal allograft rejection has become a leading cause of graft failure. Previous studies by the Principal Investigator have demonstrated that experimental corneal allografts that have been soaked in either heterologous or homologeous antibody against histocompatibility antigens have prolonged survival times and decreased incidence of rejection as compared to unsoaked grafts or those soaked in normal serum solutions. Experiments to date appear to rule out blockage of efferent rejection mechanisms as a basis of the protection. The proposed studies will elucidate the biological characteristics of histocompatibility antigens on corneal cells, the physiologic and immunologic alterations of corneal cells exposed to antibody against transplantation antigens, the fate and systemic localization of corneal cell histocompatibility antigen-antibody complexes, and the immunobiologic basis for the protection of corneal allografts by soaking in antibody. Improved methods for prolonging survival of corneal allografts with antibody will be sought. Extensive use will be made of in vitro studies using cultured corneal cells and lymphocytes. Fluorescent antibody and immunoperoxidase methods will be used to identify antigen and antibody in vitro and in vivo. In addition, radioisotope labeling will be used in conjunction with liquid scintillation counting and radioautography for more precise quantitation and localization. Further purification of antibody will be tested in experimental allograft experiments. Extensive use of inbred animals will allow investigation of the effects of corneal histocompatibility antigen-antibody complexes on host sensitization.